Piezoelectric crystal holder



Dec. 16, 1947. OLARTE ET AL 2,432,790

PIEZOELECTRIC CRYSTAL HOLDER Filed 001;. 3, 1945 ATTORNEY Patented Dec. 16, 1947 PIEZOELECTRIC CRYSTAL HOLDER Rudolph OLarte, Rego Park, and George Vollet, Freeport, N. Y., asslgnors to Jacques Kreisler Manufacturing Corporation,

North Bergen,

N. J a. corporation of New Jersey Application October 3, 1945, Serial No. 620,004

The present invention relates to piezo-electric crystal units and more particularly to piezo-electric crystal holders.

Crystal holders of the type to which the present invention relates and which comprise a base and a cover, each formed of sheet metal, have heretofore been made by soldering the cover to the base for securing and sealing these two parts together. The soldering operation has been found to be difficult and unsatisfactory. It is therefore an object of the present invention to provide a crystal holder having parts which are of such construction that they can be secured and sealed to each other without a soldering or similar operation.

The above and other objects, features and advantages of the present invention will be fully understood from the following description and the accompanying illustrative drawings.

In the drawings:

Fig. 1 is a side view of a piezo-electric crystal unit comprising a crystal holder embodying the present invention;

Fig. 2 is an end view, on a larger scale, of the unit illustrated in Fig. 1;

Fig. 3 is a view partly in elevation and partly in section of the companion parts of the crystal holder of the present invention, showing the parts before they are assembled;

Fig. 4 is an enlarged view partly in elevation and partly in section of the end portion of the cover of the crystal holder before it is assembled with the base;

Fig. 5 is an enlarged fragmentary view partly in elevation and partly in section of the base and cover in secured relation, the other parts of the crystal unit being omitted.

Referring now to the drawings in detail there is shown in Fig. 1 a piezo-electric crystal unit I0 comprising a holder I2 in which a piezo-electric crystal I4 is mounted. Said holder comprises a base l6 and a cover l8. Said base is provided with terminal prongs 20 which are sealed in companion openings 22 by glass seals as indicated at 24 whereby said terminal prongs are secured to the base in insulated relation thereon. It will be understood that said terminal prongs 20 are operatively connected in any usual or well known way to the crystal H, which is mounted within the holder. Also, it will be understood that before the base and cover are secured to each other, the prongs 20 are sealed in the base by the glass seals 24 and the crystal is operatively connected to said prongs; the base and crystal being first 2 Claims; (Cl. 171-327) 2 assembled after which the cover is secured to the base.

As illustrated, in Fig. 3, the cover [8 is in the form of a cupped member which is completely closed except at one end thereof. Said cupped member is preferably formed of soft brass but may be formed of other suitable sheet metal or of any other suitable material. At its open end cover I 8 is provided with a laterally outwardly offset peripheral portion 25 which defines an internal peripheral shoulder 26 which forms a seat for the base It when the cover and the base are assembled and secured to each other. Peripheral end portion 25 has a peripherally extending end part 27 of tapering thickness as clearly shown in Figs. 3 to 5. The base [6 is formed of suitable sheet metal, for example Kovar, which permits the sealing of the prongs 20 to the base by the glass seals 24. Said base has a flat portion 30 in which the openings 22, for the prongs and glass seals are provided, and a peripheral flange 32 which projects from and transversely to the outer surface of the flat portion 30 of the base completely therearound.

When the base [6 and the cover l8 are in assembled relation the marginal edge portion of the flat part 30 of the base engages the seat or shoulder 26 of cover It, and said base and cover are secured to each other by curling or rolling the end part 28 of the cover over the flange 32 of the base, substantially as illustrated in Fig. 5. Preferably a sealing composition such as a plastic cement is applied to the adjacent portions of the cover and base, as indicated at 34 (Fig. 5) I before the end part 28 is curled or rolled over the flange of the base whereby to provide a fluid impervious seal between the cover and the base. Thus, when the cover is secured to the base with which the crystal is just assembled, the crystal is completely sealed within the housing which is constituted by the cover and the base.

Thus, it is seen that the crystal holder described above is well adapted to accomplish the objects of the present invention. It will be understood, however, that various changes in the details and construction and in the arrangements of parts may be made without departing from the underlying idea or principles of the invention within the scope of the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. In a piezo-electric crystal unit, a holder for the crystal comprising a base in which terminal prongs are mounted and sealed, and a cover forming a completely closed and sealed housing for the crystal mounted therein, said cover having a side wall and a. peripheral end portion oflset laterally outwardly of said side wall and defining an internal peripheral shoulder providing a seat for the base, and said base having a flange over which a part of said end portion is bent for securing the base and cover to each other, and a sealing composition interposed between said bentover part of said cover and the confronting peripheral portion of the base and cover for providing a fluid-tight seal between the base and cover.

2. In a piezo-electric crystal unit, a holder for the crystal comprising a base in which terminal prongs are mounted and sealed, and a cover forming a completely closed and sealed housing for the crystal mounted therein, said base having a peripheral flange projecting from the outer side of the base transversely thereof, said cover having a side wall and a peripheral end portion ofiset laterally outwardly of said side wall and defining an internal peripheral shoulder providing a-seat for the marginal edge portion of the inner Number REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 951,023 OBrien Mar. 1, 1910 1,607,923 Sebell Nov. 23, 1926 2,203,486 Bond June 4, 1940 2,203,545 Peterson June 4, 1940 

